1979 GMC C1500 heat riser issue

1979 GMC C1500
95,000 MILES • V8 • 4WD • AUTOMATIC
Avatar
RYAN797
  • MEMBER
  • 1 POST
HI there I have a '79 gmc pickup and the fellow I bought it from rebuilt the motor and took off some emmisions stuff (no big deal in IDAHO) but he also took off the heat riser vacuum and arm, the valve does not have the counter weight on it or the thermostatic spring so it just flaps around opening and closing on its own... I need to know which way to wire up the valve so as to keep it open and not cook that side of the engine. The tab on the valve can be pulled to the front of the truck or toward the back.... whick way is open.

Thank you for the time and help... ryan
Dec 27, 2008 at 7:28 PM
Advertisement
Avatar
RASMATAZ
  • ✓ASE Certified Mechanic
  • 75,992 POSTS
  • ASE Certified Mechanic
The the valve should be towards the back so that the intake air will not overheat. When the valve is on the close position it helps on fuel evaporation for better combustion during initial cold start when the engine comes to normal temp it is not longer needed.
Dec 27, 2008 at 7:50 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.